Suspect my windows or area surrounding is leaking.  During rain, water seems to flow out from under the paint/cracks surrounding the window.  Pretty severe during heavy rain, actually can form a pool on the floor on some occasions.

Contractor has not surveyed site but has suggested PU injection.  Quoted over RM 1k.  Area is just 3 aluminium windows in single frame.

Is that rate normal?  Any other recommendations?  Is DIY possible or advisable in this instance?